Continuous-flow traffic interchange



KENTARO OKUBO CONTINUOUS-FLOW TRAFFIC INTERCHANGE March 8, 1966 2Sheets-Sheet 1 Filed Dec.

March 8, 1966 KENTARO OKUBO CONTINUOUS-FLOW TRAFFIC INTERCHANGE 2Sheets-Sheet 2 Filed Dec. 19 1962 United States Patent 3,23%,854CDNTlNlUQUS-FLGW TRAFFEC HNTERCHANGE Kentaro (limbo, 1-437 Saginorniya,Nakano-ku, Tokyo-to, .lapan Filed Dec. 19, 1962, Ser. No. 245,778 Claimspriority, application Japan, Dec. 22, 1961, 36/ 46,320 1 Claim. (Cl.94-11) This invention relates to traffic intersections, and moreparticularly it relates to intersections or interchanges which are sodesigned as to permit continuous flow of trafiic on intersectingstreets.

The term street is herein used in the sense of its including roads,highways, avenues, boulevards, and the like, each of which carriestraffic in at least one direction and, in most cases, in two mutuallyopposite directions. It will be obvious that the invention is applicablealso to intersection of streets with other right of way such as railwaylines.

With the ever-increasing number of vehicles, trafiic congestion is amajor problem in numerous places throughout the world, and the primeproblem in alleviating this congestion inevitably converges to that ofefiicient handling of traific at intersections.

The present invention in its broader aspects contemplates providing anew street intersection means of relatively simple construction disposedwithin the confines of the thoroughfare or the so-called right of way,wherein, by utilizing multi-level crossing and avoiding grade crossing,continuous and smooth traflic flow and increase in traific handlingcapacity are realized, and trafiic interruptions, delays, interference,and accidents are preented.

Fundamentally considered, a grade crossing is created by the impositionat an intersection center of one street on another street directed in adifferent direction. In endeavoring to avoid grade crossing, the mereseparation of traffic flows by resorting to diiierent levels isunsatisfactory since this leads to multiple overlapping or stacking ofdifferent levels at the intersection center, this stacking increasingexcessively with the increase of interchange requirements. The presentinvention, briefly described, contemplates preventing this excessivestacking by directing the route of each inbound vehicle intending tomake a left turn (in the case of right-hand trafiic) to pass always overa U-shaped, elevated bridge up to the cross street so as to cause thesaid vehicle to make a remote detour before it passes beyond theintersection center, the said elevate-d bridge being built over theother lanes and having one end communicating with the intersectioncenter part and the end communicating with a grade passage; anddirecting the lanes of the street forming the intersection tocommunicate with the intersection center part, the through lanes beingdirected in straight lines and crossing at two levels, whereby gradecrossing is avoided.

The nature and details of the invention will be more clearly apparent byreference to the following description taken in conjunction with theaccompanying drawings in which like parts are designated by likereference numerals and letters, and in which:

FIG. 1 presents views showing one embodiment of the invention as appliedto an intersection of two streets, FIG. 1(A) being a plan view, FIG.1(B) being an elevational view, as viewed toward x of FIG. 1(A), andFIG. 1(C) being an elevational view, as viewed toward y of FIG.

FIG. 2 presents views showing the basic configuration of the interchangeaccording to the invention, FIG. 2(A) being a plan view, FIG. 2(B) beingan elevational view toward y in FIG. 2(A) (the part G being an elevatedoverpass), and FIG. 2(C) being an elevational view toward y in FIG. 2(A)(the part G being a depressed underpass).

Referring to FIG. 1, the axes of the intersecting streets will bedenoted respectively by xx' and yy. A crossing throughway A (an overpassin this case) crossing three-dimensionally over the street x-x' in thedirection y-y' is provided, and the two ends of the crossing through-Way A are connected to the leg y and leg y of the street y-y by ramps.Reference letters B, C, D, and E designate U-shaped elevated roadways,each bridging over, respectively, one of the four legs x, y, x, and y ofthe two streets in the vicinity of the intersection center, the concavesides of the U-shaped roadways B and D mutually facing each other, andthose of roadways C and E mutually facing each other. The elevatedroadways B and D are connected, respectively, to the grade-level streetx-x' by ascending ramps a and from the direction of the intersectioncenter part and by descending ramps b and [2 toward the intersectioncenter part. The elevated roadways C and E are connected, respectively,to the street yy' by ascending ramps a and a, from the intersectioncenter part and are connected to center crossing throughway A byconverging lanes b and b.,. Accordingly, the elevated roadways A, B, C,D, and E and the lanes [1 and b, are disposed in substantially the samehorizontal plane.

The traffic flows of the interchange of the abovedescribedconstructional arrangement will now be described in detail. The flow ofthrough traffic in the y y direction passes under (crossesthree-dimensionally) the elevated roadway E as indicated by arrow 1,enters the throughway A at arrow 2, passes under (crossesthreedimensionally) the elevated roadway C at arrow 3, and proceedsthrough toward y. The flow of traffic in the y x direction flows asindicated by arrows 4, 5, and 6, passing under the lane [1 separatesfrom path 6, enters the ascending ramp a flows as indicated by arrows 8and 9 along the roadway D, converges at portion 10 with the trafiic inthe x'- x direction, passes under (crosses three-dimensionally) thethroughway A at arrow 11 and under the roadway B at arrow 12, andproceeds toward x. The flow of traffic in the y x' direction flows alongthe path indicated by arrows 4, 5, 6, and 7, converging with the trafficin the xe x direction, passes under (crosses three-dimensionally) theroadway D, and proceeds toward x.

Similarly, the traflic in the x' x direction flows as indicated byarrows 13, 14, and 15 in sequence; the traffic in the x y directionflows as indicated by arrows 16, 17, 18, 19, and 20 in sequence; thetraffic in the x+y direction flows as indicated by arrows 16, 17, and18, then, separating from path 18, flows as indicated by arrows 21, 22,23, 24, 25, 26, and 27 in sequence; the traffic in the y y directionflows as indicated by arrows 2 8, 29, 30, and 31 in sequence; thetraffic in the y' x direction flows as indicated by arrows 32, 33, and12 in sequence; the trafiic in the yex' direction flows as indicated byarrows 32, 33, 34, 35, 36, 37, and 38 in sequence; the traffic flow inthe xx' direction flows as indicated by arrows 39, 40, and 38 insequence; the traffic flow in the x y direction flows as indicated byarrows 41, 42, 43, and 44 in sequence; and the traffic in the x+y'direction flows as indicated by arrows 41, 42, 43, 45, 46, 4-7, 48, 49,and 50 in sequence.

Since, as described above, the division of traffic flows is thorough,the most important conditions relating to interchanges are fulfilled,that is, (1) weaving is prevented, (2) decision on three drivingconditions at one point is not required, and (3) there is no mergingwith or exit from the right lane. Furthermore, the interchange asdescribed above affords economy of land area and simplicity of trafficflow and of construction, wherefore the interchange facilitatesdesigning to suit any intercharge requirement and, moreover, affordslowering of costs. That is, this interchange is highly suitable forincreasing trafiic handling capacity as a total result although thespeed of the left-turning trafiic is sacrificed somewhat.

The fundamental form of the concept of the present invention isdiagrammatically indicated in FIG. 2, in which the center roadway isdesignated by reference letter G. in FIG. 2, reference letters B and Cdesignate U-shaped crossing roadways crossing three-dimensionally overextensions of street legs of the center roadway G. The roadways B and Care respectively connected, at one end of each, to the center roadway Gby connecting roadways b and provided on both sides of the centerroadway G. The roadways B and C are further connected, at the other endof each, to the grade level street by ramps a and a respectively, thesaid ramps being open at their ends communicating with the grade levelstreet. The level of the center roadway G is above or below depending onthe place of use as indicated in FIG. 2(8) and FIG. 2(C).

The above-described constructional arrangement is based on the followingconditions. Elevated U-shaped bridges adapted to fit within the width ofthe streets at the site where the interchange is to be constructed aredisposed on the two ends of the intersection center part A with theirrespective exits and entrances always facing the center part A, eitherof the exit and entrance of each elevated U-shaped bridge being made tocommunicate with the grade level street, and the other being made tocommunicate with a path which detours remotely from the center part Gand is directed, by way of the center part G as an intermediary medium,toward the intended destination route; and a vehicle intending to travelon an elevated U-shaped bridge is caused to enter the route leading tothe said bridge before the vehicle arrives at the center part A and tocomplete a U-turn prior to its arrival at the center part A. In actualapplication, the above-described structural arrangement is taken as asingle unit, and, in accordance with the requirements of interchange, asingle unit is used, or a plurality of units are used at varied anglesand in three-dimensional superposition. Accordingly, the interchangeaccording to the present invention can be applied in a planar manner tointersections of any number of ways or street legs such as, for example,three-way and four-way intersections, and can be used in athree-dimensional manner for intersections of any number of ways withany number of levels.

Thus, the interchange of this invention does not occupy a large space asin the case of many conventional interchanges for the same purpose.Consequently, it can be built freely above and below ground level.Furthermore, this interchange does not cause confusion for drivers usingit, and since the selection of and decision on the 4. intendeddestination route can. be made freely and easily at the place ofintersection, there is no necessity of excessive travel in order tochange travel direction as in the case of some conventional systemscomprising a network of streets with combinations of intersections atseveral places, and there is no possibility of confusion and congestionwithin an urban area. Therefore, the interchange according to thepresent invention is highly suitable, convenient, and advantageousparticularly for intersections of urban streets.

Although this invention has been described with respect to specificembodiment thereof, it is not to be so limited since changes andmodifications can be made therein, as will be obvious to those skilledin the art, which are within the full intended scope of the invention,as defined by the appended claim.

What is claimed is:

A continuous trafiic flow interchange for two intersecting streets, thefirst street passing under the second street at the point ofintersection, a U-shaped cross bridge spanning each of said streets andtransverse thereto on each side of and spaced outwardly of said point ofintersection, the concave portions ot the bridges facing said point ofintersection, each cross bridge having an inlet side leg and an outletside leg, a central longitudinal portion of each street defining athroughway, the inlet side legs of said cross bridges being positionedoutside of said throughways and inclined from street level, the outletside legs of each cross bridge communicating with the throughwayadjacent thereto communication with said first street being at streetlevel and communication with said second street being at the overpassingportion of the second street, the first street communicating with theinlet side legs of the cross bridges on the second street and the secondstreet communicating with the inlet side legs of the cross bridges onthe first street.

References Cited by the Examiner FOREIGN PATENTS 12/1928 Great Britain.

OTHER REFERENCES CHARLES E. OCONNELL, Primary Examiner.

JACOB L. NACKENOFF, Examiner.

N. C. BYERS, Assistant Examiner.

